Growth of Japanese holly as affected by nitrogen and growth regulators

Abstract

The effects of 3 nitrogen levels and 2 growth regulators on growth of winter and summer propagated cuttings of Ilex crenata cv. Helleri were studied. Nitrogen applications promoted bud break after rooting of summer cuttings and also enhanced the growth of winter rooted cuttings. Generally, plants grown at 300 and 150 ppm N had greater initial shoot numbers and length, secondary shoot numbers and length, height, width, fresh weight, and dry weight compared to plants grown at 50 ppm N. Initially, benzyladenine (BA) at 600 ppm decreased the number of primary breaks and decreased the stem length, while gibberellic acid (GA) at 400 ppm decreased the number of primary bud breaks and increased stem length. The hormone responses persisted for approx. a month, starting a fortnight from the first application. GA₃ + BA caused very erratic responses. There were no N-growth regulator interactions.